Valve mechanism for pneumatic tools.



, \\MN| N Q U," u@

a GA. OLI-vm. I VALVE MB'GH'ANISM PoR PNBUMATIG TooLs.

A PP-LIGATIQNv FILED APR; 7. 1913.

ot' this specification. y y invention relates to miprovements nl valvefniechanism for pneumatic tools and Cil ericsson e. onrvnn, or DENVER, camerino, assiettes To THE STANDARD ROCK- nrtrrct. cOraraNY, or neuves., oorlonan'o, a CORPORATION OFOOLORADO;

VALVE MEClffllillTISlVI FR PNEUMATC TOOLS.

Specification of'Ilejtters-atent.

Application filed .April '27, 191.3. Serial No. 759,307.

' To all whom it may concern.

Be it lrnou'n that ll, GEORGE A.- OLrvnR, a

useful Improvements in Valve'Mechanism tor Pneumatic Tools; and l, do declare the' following to he. aA full, clear, and exact deysc r'iption ,o-, tlieinvention, such as will en.- ahleothers skilled 1n theart to which it ap-y pertains to make and use the same, reference beinghad to thc accompanying -dra\vings, and yto the letters and tigures of rete'rence marked thereon, which. torni a part maybe said to constitute an improvement overgU. S. Patent. NO QGQjl-L issued to Yincentll. OBrien, ,lune 28, 1910, to which referenceniay loe` had for a, description in4 detail of the construction' and operation of the machine as a Wholev My 4present. invention relates to valve mechanism of this characterin which a cylindrical slidahly movahle4 valve employed,` the said valve having diilerential pressure 'areas at its opposite extremities, the smaller' areabeing continuously. acted upon by the live Amotive' fluid while 'the llarger area is intermittently acted upon by the live motive {iuid and the exhaust.

The object of this invention is to providea construction ot this character infwvhich the Wear incident tothe reciprocation of the 4cylindrical valve shall he reduced to a minimum. One objection `to a' valve of' this character 'is' that, owing to the sharp cor-A ners inoidentto the forming of a centrally locatedr circumferential groove, the `ad'ja cent mechanism of the 'valve has been subjected'to undue Wear; Some attempts have heretofore loeen made to overcome this dini culty, one of which is embodied 4in yUnited,

I V,nicat'ion with the extremities of longitudif-` nali y ydisposed orifices. VBy making these f1 n s i L y rorations and Oriices sutiiciently numero s'the perforations are so small that the ear' incident. to 4the 'aforesaid diiiiculty is greatly" reduced. There is,l ho'iv'ever, an" 0b-k "i `icction to the last-named constructiomfduefto the tact that in' order to construct a Valvewith these pertorations"there 'must ble suHicient lstock or 4metal topermit the' -longitudinal'lmringot the valve "from end to end',

the extremities of these horeslbeing closedl and' the :pcrtorationsr heretofore mentioned formed laterally in the valveat the extremities oi the longitudinal oriiices."."l,`liis"1e quil-ement makes it. necessary to employ a valve 'which' is heavier than is ldesirable and the consequence is that the Weight of thevalvc results in the upsetting of its' opposite extremities, due tothe pounding oA these extremities dullicult)vv incident t'o the 47Weight land. at the saine time prevent the wear 'which has lheretot'ore been incident to the sharp corners' ad?vv sultand "practically doing away with the wear usually'- incidcnt to structures of this character.vv in accomplishing*this result, l

torni a circumferential `groove of suitable,

width in therextcriorsurfaceot-'l-hc cylindrif cal valve, a'iida similar groove in the exterior surface of the .central core or stem upon which the valve is mounted and upon `Which it reciprocates during the operationlot" the tool. .l also provifilethehody ofr"tlie,valve centrally of this circumferential grooveV with a series ot small perforations "whereby 4the mot-ive iuidivhich enters the-said groove of the valve will also pass through theshellfo'f the latter and occupy the?circumferential groove formed inthe exterior of the' core or stem, 'From this it-Will he vseen that the pressure .will be the same; both,-iiiteriorly and .exteriorly of the valve producing la balanced result and relieving the mechanism from `weer, as ivill be readily understood;A

Having briefly outlined" my construction,

l will proceed' to describe the same indetail,

against their adjacent-parts'durj i ing the reciprocating;` movement ot' the valve. hiv object, therefore, is to overcome this reference being made to the accompanying i drawing, in which is illustrated an embodiwing at its .rear extremity ina base ment thereof. In this. drawing-Figure 1 is a section taken through a port-ion of a roclrdrill including valve mechanism ofthe character to wlii-ch my improvementpertains, the iin- .provenient being disclosed in the said view."

Fig. 2 .is asimilar section.v but taken on a different plane.

" The saine reference characters indicate the same parts in all'the-views. l v

-Let' the numeral 5 designate the valve'- chest or casing having a central opening in which is inserted 'a core or stem t5, terminat- 7. Mounted on 'the stem or core portion of this inem- 4bei is ahollow' cylindrical valve 8, haviiiga surface9 at-its rear .extremity of relatively large. area and a surface -10 at its forward extremity`- of a. relatively small aiea. Iii mechanisms of this vcharacter 'live motive flu-id constantly act'sfon the 'surface 6 Aof lesser area and intermittently on the surface 9 of larger area'. 4valve is centrally provided with an exterior' circumferential groove 12', which is bounded atits opposite extremities by'sli'ould'ers 13 and' 14:.' vQppovlf2-'of the Ivalve is a similar the shell site-.the groove oove 15. formedin' the core Gand 'fof tl'ievalve .'is. provided with a series of relatively small j perforations 16, whereby the two grooves VA12 and -15 communicate with each other. z

When'l this structnreis. in use, the livemotiv'e 'Huid enters 'a port 17 formed in the base 7 of the core and follows a -passage 18 of -the valve-chest, the said passage communicating communication with the l wardly through ports at* its forward extremity with a circumferential groove 19 formed in the valve-chest adjacent the cylindrical valve piece 8 and in groove 12 of the latter when thevalve piece isat its forward 4limit. of movement, (see Fig. 2). v`Wheng.

however, the valve piece 8 is 'at its rearward limit of movement, (see Fig. 1) the live motive fluid from the groove 19 passes forin the direct-ion of the arrows 20 into the hammer chamber (not shown) ofthe tool for imparting the forward movement of the hammer, the eX# haust from the chamber forward of the ham-v mer' taking place at first through a-passage 40 in the hammer cylinder L11 and a passage 21 of the valve-chest. "Practically as soon as the hammer has reached its forward limit of movement live motive fluid is introduced by a passagefl? to a small cavity 22 at the Y rear of the valve 8 and actsupoii its larger area 9 to move thevalve to its forward position. Simultaneously with the escape o f the exhaust through the passage 21 ofthe valve-chest, it also enters a passage 1 3 in the hammercylinder, a' passage 29 and-a port .ber'in front of the hammer.,

23 iii the .valve chestand 'enters a circular 65 'groove 21 in communication with the'groove 12 of' the cylindrical valve, the vsaid exhaust entering the groove 15 of the core through the smallfperforations 16. The exhaust passes'thence'from the gi'i'iove 12 of the 7o'- valve into'a circular groove of the valvechest and thence through a port 26 into a passage 9.7, andftlience to the atmosphere by way of a portV 28.' Hence, 'the pressure lofthe motive fluid in the two grooves 12 and 75 15 and acting on opposite' surfaces of the cylindrical valve, is equalized, producing a balancedV result, and this condition exists during the lforward movement of the valve heretofore explained. When 'the valvesis in 8 0 its forward position; as illust'rat'ed in FigN '2, the hammer-44 begins 'its return movelment, the live motive fluid for' this purpose passin l 1Q an `ward movement ofthe hammerthe exhaust takes placethroughpassages and 31 formed in the forward extremity-f of the valve chest and communicating with/a central passage 32, from whichthe perforations-SS into the cavity 34" in the rear of the valve, thence throughfthe port 26 to the passage 27 and thence-to the atmospheie throughaport 28. From this it `will vbeunderstoodthat during -both movements ofthe cylindrical-v valvewincident to the operation of a tool of the character in which a valve of this style is employed, the pressure of the live motiventluid-will be 'equalized on both the interior and exterior 110 surfaces of the valve, thus-practically relieving thefvalve from friction and the wear incident' thereto.

Having thusl described my invention. what I claiin'ifs:

l 1. In valve mechanism for pneumatic tools, the combination with a valve chest orcasing having a vcentrally located stem or core, of amotive fluid actuated cylindrical cated in acavity of the` chest surrounding the stem, the said'val've piece being 'exteriorly grooved for the passagey of the motive -fiuid duringr the operation of the' tool, the stein being also exteriorlygrooved adjacent the valve 1-25 valve piece l piece, the twogroove's- 'being substantiallythe saine size,l -the valve piece being' perfo,-

rated 'permit' tho-Huid to' fillthe groovev exhaust escapes through 100:

anda motive Huid'act-uated valve piece lo. cated 1n said cavity vand also exteriorly grooved for the passage of the'motive .fluid during the operation of the tool, the grooves of the valve piece and stem being of substantially equal capacities, and incommunication, for the' purpose set forth.

3. he combination of a valve chest having a centrally located core separated from the body of the chest by a cavity and having a circumferential groove in communication with the cavity, and a cylindrical valve piece slidably mounted in said- .cavity'and also exteriorly grooved, the two grooves being in communication and of substantially equal capacities for balancing purposes.'v

4. Thecombination of a valve chest orl casing having a centrally located core and 25 a cylindrical `valve located in a cavitysurrounding the core and mounted to reciprocate therein, the valve piece. and the core ,havingY intercommuni'cating l circumferential grooves of similar capacities. adapted to receive motive fluid during the operation of thetool. `v e..

5. The combination of a valve chest or casinghaving a central stem and an annularly arranged .cavity between the stem and .ing Vgrooves of substantially equal capacities` the bodyofthe chest, and a valve piece located in said cavity, the valve and core vhavintercommunicating circumferential adapted'to receive motive fluid during the operation ofthe tool, the valve piece having differential pressure areas and being mounted yto reciprocate under the influence of the motive lfluid employed in the operation'of the tool.

6. The combination of a valve chest hav- 'th'e" said cavity, the said valvepiece and Astem having circumferential intercommunicating grooves f substantiallyl equall capacities, the chest adjacent. the valve piece also having additional circumferential grooves cooperating with the groove of the valve piece vto facilitate the passage ofthe motive' luid for tool' operating purposes.

7. In valve mechanism for pneumatic tools, the combination of'a valve chest having a centrally located 4stem or core surrounded by an annular cavity, the bodyof the chest havinggrooves, ports and passages through which the motive fluid passes during vthe operation of the tool, and a valve piece located in lSaid cavity and surrounding the core, the said valve piece and core having adjacent circumferential intercommunieating grooves of substantially equal capacities, also in communication With certain grooves, ports and passages, of ythe lvalve chest, the valve piece being mounted'to 'rel ciprocate and having diiferentialpressure said purpose, substantially as described.

8. In a device o-f the class described, thec'ombination of a valve chest or casing having a. centrally located core, and an interposed annular' cavity and a cylindrical valve piece mounted to reciprocate in said cavity, the valve piece and core h ving intercommunicating circumferential 'ooves of substantially equal capacities, substantially as described.

.9. In combination a valve chest, having.

a centrally located core, the latter being provided exteriorly With a circumferential groove, a cylindrical `.valve piece slidably mounted upon said core and also exteriorly grooved cirCumferentiaHy, means for introducing'live air to both grooves during the operation of the valve, said grooves being so arranged that the greater portion of the one .in the valve piece Will lie opposite that in the core in all positions of the valve piece.

10. In combination a 'valve chest having a centrallylocated core, the latter being provided exteriorly with a circumferential groove, a cylindrical .valve piece slidably mounted upon said core and also exteriorly grooved circumferentially, said valve piece `areas upon which the motive fluid acts for havingperforations' therethrough for plac- GEORGE A. OLIVER. lVitnesses:

A. J. QBRIEN, "0. M. W'AUDBY. 

